Tn-Mucin 1 antigen (Tn-MUC1)

The **Tn-Mucin 1 antigen** is a tumor-associated carbohydrate epitope found on the mucin 1 (MUC1) protein. In healthy epithelial tissues, MUC1 is a highly glycosylated transmembrane protein expressed on the luminal surface. In many carcinomas—including ovarian, pancreatic, triple-negative breast cancer, and non-small cell lung cancer—MUC1 undergoes aberrant O-glycosylation resulting in exposure of truncated glycans such as the *Tn* antigen (\(\alpha\)-GalNAc-O-Thr/Ser). This altered form is referred to as *Tn-MUC1* or *tumor-associated Mucin 1*, distinguishing it from normal tissue expression. The presence of the exposed *Tn* epitope creates a neoantigen that can be specifically targeted by immunotherapies such as chimeric antigen receptor (CAR) T cells engineered to recognize this structure. These therapies aim to selectively eliminate tumor cells while sparing normal tissue due to differential glycosylation patterns. The specificity for tumors arises because healthy tissues typically mask these epitopes through further glycan extension. Clinically, detection of *Tn*-modified MUC1 serves both as a biomarker for patient selection and an actionable target for novel therapeutics like autologous CAR-T products. However, safety concerns remain regarding potential cross-reactivity with normal tissues expressing low levels or transient forms of this epitope. In summary, **Tn-Mucin 1 antigen** represents an important therapeutic target in oncology due to its restricted expression pattern and role in immune evasion by tumors.[3][4][6]

Other names

Tn-MUC1 antigenTumor-associated Mucin 1 (Tn-modified)MUC1-TnMucin 1 with Tn glycan modificationSynthetic MUC-1 (di-Tn) glycopeptide[2]

Targeted immune cell recognition and killing of tumor cells expressing the aberrant glycoform of MUC1 via chimeric antigen receptor (CAR) technology[3][4]